Fred, probably the "safe" thing to do is put a resistor on the line to the fuel gauge but I'm one of those Waldo is referring to. I converted my old 55.1 panel to 12v and never gave a thought to needing to drop the voltage to the gauges or heater motor. All I did under the dash was change to 12v bulbs. I put over 100K on the truck after the conversion with nary a problem.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.